Throughout the first and second line, the left hand has no phrasing. It should only bother to play the notes in full value, while the right hand, for phrasing reasons, has little portamento slurs on the 2d and 4th beat of each staff. Obviously these slurs are accompanied by an hairpin that indicates a diminuendo on the second note.
In the last staff is introduced the phrase slur for the left hand, and the hand must be raised every 2 beats.
The piece begins with a p (piano) that then becomes f (forte) on the pivotal part of the theme. Obviously for each portamento slur is specified the dim(diminuendo).
The theme, within the piece, is reprised several times and always has the same dynamic: p, dim, dim, f/p (forte piano), dim, dim, f / while in the last staff we have a major change: mf, dim, f.